The present invention relates to a walker or cane for assisting and supporting walking movement. More particularly, the present invention relates to a hinged or flexible walker assembly or cane assembly.
Adjustable walkers for use in conjunction with stairs, steps, and the like are known in the prior art. For example, both U.S. Pat. No. 3,387,617 to Reiber and U.S. Pat. No. 3,176,700 to Drury, describe a walker having two adjustable front legs that can be telescopically extended or retracted, and locked into position to aid in descent or ascent of stairs. This concept is further developed in U.S. Pat. No. 4,777,973 to Nakajima, which describes independently extensible or retractable front and rear legs. However, in all these designs extension or retraction occurs co-linear to the main shaft, and the legs are not assured of maintaining a substantially perpendicular position with respect to the ground on uneven surfaces or terrain.
In an attempt to reduce the energy required to use walkers, and to compensate for sloping terrain, walker designs in which the rear and front legs are pivotally movable with respect to each other have been disclosed. For example, U.S. Pat. No. 2,656,874 to Robb discloses such a simple spring assisted walker, while U.S. Pat. No. 4,742,838 to Muiza et al. discloses a more advanced swinging leg walker system. However, these systems still do not simulate certain aspects of normal walking, including dorsiflexion and plantar flexion of a foot, and do not permit substantially perpendicular orientation of the legs with respect to the ground under varying terrain conditions.
What is needed is a hinged or flexible walking assist device that simulates dorsiflexion and plantar flexion of a foot, thereby improving speed and comfort of a walker using a walking assist device. In addition, such a hinged or flexible walking assist device operates in varying terrain conditions by adapting the position of the legs to remain substantially perpendicular to the ground, increasing the balance of a user, and increasing speed and security of walking for the user. The present invention satisfies these needs by provision of a walker assembly for assisting walking movement, with the walker assembly including a first side rail assembly having a first gripping rail configured to be manually grasped and a second side rail assembly having a second gripping rail configured to be manually grasped. At least one connecting rail is attached between the first and second side rail assemblies.
A first leg assembly is pivotally connected to the first side rail assembly and a second leg assembly is pivotally connected to the second side rail assembly, with pivotal movement of the first and second leg assemblies normally being independent of each other. Optionally, a first mechanism constrains pivotal movement of the first side rail assembly and the first leg assembly. In one preferred embodiment, an elastic element such as a cord, tension, or built-in, hinge-mounted circular spring having a predetermined spring constant is attached, typically between the first side rail assembly and the first leg assembly, to limit the permissible rotation of the first side rail with respect to the first leg assembly. Similarly, a second mechanism constrains pivotal movement of the second side rail assembly and the second leg assembly. Again, in a preferred embodiment an elastic element is attached between the second side rail assembly and the second leg assembly to limit rotation of the second side rail with respect to the second leg assembly. As will be appreciated, additional, secondary elastic elements or friction devices can also be employed to provide a biased forced counteracting a primary elastic element. The spring constants of these elastic elements can optionally be adjusted to alter the tilt of the upper portion of the walker with respect to the leg assembly when the walker is used. In addition, in preferred embodiments, the first leg assembly has a front leg integrally attached to a back leg, and the second leg assembly similarly includes a front leg integrally attached to a back leg, with this integral connection effectively increasing rigidity and stability of the walker assembly.
In an alternative embodiment of the present invention, a walker assembly for assisting walking movement includes a side rail assembly having a gripping rail configured to be manually grasped, with the side rail assembly constructed to form a rigid unit when used. A dual leg assembly having front and backs legs is rigidly connected to each other, with the dual leg assembly pivotally connected to the side rail assembly. Also provided in this embodiment is a mechanism that pivotally connects the dual leg assembly to the side rail at least at one hinge point to allow pivoting movement of the dual leg assembly with respect the side rail assembly. Of course, as those skilled in the art will appreciate, multiple hinge or other pivoting linkage mechanism can also be used in the present invention to provide the required pivoting motion. In addition, this pivoting motion of the side rail assembly can be constrained by provision of elastic cords, compression or tension springs, leaf springs, plastic bumpers, or other mechanisms known to those skilled in the art to dynamically limit movement. For certain embodiments, it is possible to lock or otherwise disable action of the elastic cords, springs, bumpers, etc., to lock the walker into a fixed, rigid position. In particularly preferred embodiments, a constraining mechanism such as an elastic element limits rotation of the side rail assembly with respect to the dual leg assembly to about a 20 degree arc. Of course, as required the rotation limit can be adjusted to permit greater or lesser rotation of the side rail assembly.
Yet another alternative embodiment of the present invention provides a walker assist device for aiding walking movement that includes a grip assembly configured to be manually grasped. An upper shaft is rigidly configured and connected to the grip assembly, and a lower shaft is pivotally connected to the upper shaft. A leg assembly is connected to the lower shaft for ground contact. The pivotal connection can include constrained mechanical hinge type connections, or may include a flexible link attached between the upper shaft and the lower shaft, with the flexible link configured to elastically bend. This latter arrangement is particularly useful for use in conjunction with canes.
Additional objects, features, and advantages of the present invention will be apparent upon consideration of the following detailed description and accompanying drawings.